Evaluation Of Diatomaceous Earth, Bean Trash Ash, Maize Cob Ash And Neem Seed Cake Powder For The Control Of Sitophilus Zeamais Mostchulsky

Abstract

Local botanical products and inert dust were evaluated in the laboratory for their ability to confer protection to stored maize grains against damage by Sitophilus zeamais Motschulsky.  Bean trash ash, maize cob ash, neem seed cake powder and Kensil Superfine dust were admixed with 100g maize grains at dosage rate of 0.9% w/w to assess for mortality and progeny emergence.  The botanical products and inert dusts were compared with two commonly used insecticides (Actellic Super^® and Spintor^® dusts) and commercial Dryacide^® inert dust.  After thoroughly tumble - mixing the grains in the plastic jars, 30 unsexed 2-week-old adult individuals of S. zeamais were added and, mortality assessed after 14days exposure by counting the dead insects.  All the insects were discarded and the grains held undisturbed for a further 56 days to assess progeny emergence. More than 20 adult emerged from untreated grain whereas treatment with Actellic Super^® or Dryacide^® resulted in zero or less than three emergences, respectively.  Spintor^® dust, Kensil Superfine^® dust, maize cob ash and bean trash ash resulted in less than five and ten adult emergences, respectively; an inadequate degree of control.  Neem seed cake powder was ineffective against S. zeamais and resulted in 15 adult emergence.  Although Kensil Superfine^® dust resulted in 85.8% mortality of the adults placed on the grains; the adult emergence that followed indicates that it is unsuitable for use as a good alternative to synthetic insecticides.  Further studies aimed at improving its efficacy are recommended.